Honors Biology Spring Semester Final Exam Study Guide

Honors Biology Spring Semester Final Exam Study Guide Flashcards

What are the 4 phases of the cell cycle and describe major events of each phase?

G1 (Gap 1): Cell growth and normal functions. S (Synthesis): DNA replication. G2 (Gap 2): Preparation for mitosis. M (Mitosis): Cell division.

When would a G0 cell re-enter G1 phase?

When there's a need for cell division due to damage or growth signals.

List the phases of mitosis?

Prophase, Metaphase, Anaphase, Telophase.

Label the sister chromatids and centromere on a chromosome.

Sister chromatids: Identical copies of a chromosome. Centromere: Region where sister chromatids are joined.

Define stem cell.

A cell with the ability to differentiate into various cell types.

Define tumor.

A mass of abnormal cells.

What are the role of the tumor suppressor gene and the proto-oncogene in preventing cancer?

Tumor suppressor gene: Regulates cell division and prevents uncontrolled growth. Proto-oncogene: Involved in normal cell growth and division; can become an oncogene if mutated.

Describe the structure of DNA.

Double helix structure with nucleotides, nitrogen bases (A, T, C, G), hydrogen bonds, and a sugar-phosphate backbone.

What are the differences between DNA and RNA?

DNA: Double-stranded, deoxyribose sugar, thymine (T). RNA: Single-stranded, ribose sugar, uracil (U).

What is transcription and where does this take place in the cell?

Synthesis of RNA from a DNA template. Takes place in the nucleus.

mRNA, tRNA, and rRNA – Where are they located in the cell and what is their function in protein synthesis?

mRNA: carries genetic code from nucleus to ribosomes. tRNA: Transfers amino acids to ribosomes during protein synthesis. rRNA: Component of ribosomes.

Describe DNA polymerase and RNA polymerase and what are their functions? How are they similar? Different?

DNA polymerase: synthesizes DNA. RNA polymerase: synthesizes RNA from a DNA template.

Which type of RNA has a codon, and which type of RNA has an anticodon? What is the purpose of the codon and anticodon?

mRNA has codons, tRNA has anticodons. Codons and anticodons facilitate the correct order of amino acids.

What occurs during translation and where does this take place in cell?

Synthesis of a protein from mRNA. Takes place in the ribosomes.

Transcription is when _ is used to make ____. Translation is when _____ is used to make ___.

Transcription is when DNA is used to make RNA. Translation is when RNA is used to make protein.

Create an analogy for amino acid and protein.

Amino acid is a building block and Protein is the final structure

What is the difference between a frameshift mutation and a point mutation?

Frameshift: Insertion or deletion of nucleotides, alters the reading frame. Point: Single base substitution.

Name and describe (or show through example) two frameshift mutations. Name and describe (or show through example) two point mutations.

Frameshift: Insertion (add a base), Deletion (remove a base). Point: Substitution (replace one base with another).

What is meiosis?

A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell.

How are mitosis & meiosis similar? Different?

Mitosis: Cell division for growth and repair (somatic cells). Meiosis: Cell division for sexual reproduction (gametes).

What type of cell goes through meiosis?

Germ cells

Define haploid, diploid, crossing over, homologous chromosomes, fertilization, gamete, somatic.

Haploid: one set of chromosomes. Diploid: two sets of chromosomes. Crossing over: exchange of genetic material. Homologous chromosomes: chromosome pairs. Fertilization: fusion of egg and sperm. Gamete: sex cell. Somatic: body cell.

Define homologous pairs and explain how this term relates to meiosis.

Pairs of chromosomes with the same genes. Relates to meiosis because they separate during meiosis I.

What is a karyotype?

A display of chromosome pairs of a cell arranged by size and shape.

What does the following statement mean? “Down Syndrome is a form of nondisjunction.”

Down syndrome is caused by nondisjunction, the failure of chromosomes to separate properly during meiosis.

Gregor Mendel – Who was he and what did his experiments consist of?

He was the father of genetics; studied pea plants to understand inheritance.

What is Mendel’s Law of segregation?

Allele pairs separate during gamete formation.

What is Mendel’s law of independent assortment?

Genes for different traits assort independently during gamete formation.

What is the phenotypic and genotypic ratio of two heterozygotes for a trait that is inherited the Mendellian way (basic dominant and recessive inheritance)? Show your work to support the ratio.

Phenotypic ratio: 3:1. Genotypic ratio: 1:2:1 (assuming Mendelian inheritance).

What is the phenotypic ratio of the cross between two individuals that are heterozygous for two traits? (hint: dihybrid)

9:3:3:1

Define dominant, recessive, heterozygous, homozygous.

Dominant: allele that masks the expression of another allele. Recessive: allele that is masked by a dominant allele. Heterozygous: having two different alleles for a trait. Homozygous: having two identical alleles for a trait.

Clarify the difference among the following terms…allele, gene, and trait.

Allele: variant of a gene. Gene: segment of DNA that codes for a trait. Trait: characteristic.

Describe and give an example of codominance, multiple alleles, x-linked traits, and polygenic traits.

Codominance: Both alleles are expressed (e.g., blood type AB). Multiple alleles: More than two alleles for a gene (e.g., blood type A, B, O). X-linked: gene located on the X chromosome (e.g., hemophilia). Polygenic: trait controlled by multiple genes (e.g., skin color).

What are the differences between monohybrid and dihybrid crosses?

Monohybrid cross involves one trait, dihybrid cross involves two traits.

What are the distinguishing characteristics on a karyotype for individuals with Turner’s Syndrome, Klinfelter’s Syndrome, Down’s Syndrome? Explain how we know all of these syndromes are forms of nondisjunction.

Turner's Syndrome: XO. Klinefelter's Syndrome: XXY. Down's Syndrome: Trisomy 21. All result from nondisjunction (failure of chromosomes to separate properly during meiosis).

What is meant by P generation, F1 generation, F2 generation?

The first set of parents crossed, F1 is the first generation offspring, F2 is the second generation offspring.

Using P, F1, and F2 generations, show an example of how recessive traits “skip” a generation. List genotypes of each generation and show punnett squares. (hint – Mendel’s pea plants; tall or short)

In the F1 generation the heterozygotes do not express the recessive phenotype, however they pass on the allele to the F2 generation who display it once homozygous recessive

What are the possible genotypes for human blood types? Is the present of Rh factor dominant or recessive? Is A, B, O dominant or recessive?

A: IAIA or Ai
B: IBIB or Bi
AB: IAIB
O: ii
Rh+ is dominant, Rh- is recessive, A and B are codominant to O.

What is the purpose of Gel Electrophoresis?

To separate DNA fragments based on size.

What is happening to DNA during Gel Electrophoresis?

DNA fragments move through the gel based on their size and charge.

What are some real-life examples of when gel electrophoresis is used?

Forensics, paternity testing, DNA fingerprinting.

What is the purpose of a restriction enzyme in Gel Electrophoresis?

To cut DNA at specific sequences.

What is the benefit of using multiple/differing restriction enzymes?

To create different fragment sizes for more accurate analysis.

What is a gene pool?

The total collection of genes in a population.

How would the allele frequency appear in a gene pool with 2 possible types of alleles, one allele being very fit, the other allele not being fit?

The fit allele will be more prominent.

What is natural selection?

Differential survival and reproduction based on heritable traits.

What is an adaptation?

A trait that enhances survival and reproduction in a specific environment.

If allele A were more fit than allele B and a selective pressure change occurs to make B more fit, describe how this will change the allele frequencies within the gene pool.

Allele B will increase in frequency, allele A will decrease in frequency.

How does allele frequency impact genotypic and phenotypic frequencies?

Allele frequency affects the number of organisms that express those genes.

How do allele frequencies relate to survival of the fittest?

Survival of the fittest means that the more fit alleles increase in frequency since the organisms that possess them have high survival rate and can reproduce to pass on their adaptive genes.

How are the Galapagos tortoises used to explain natural selection?

Tortoise neck length differed depending on the island; those with longer necks survived better where food was higher up.

What is speciation? How does reproductive isolation lead to speciation?

Formation of new species. Reproductive isolation prevents gene flow leading to speciation.

Describe the types of isolation that can lead to speciation.

Temporal isolation: different breeding times. Geographic isolation: physical barrier. Behavioral isolation: different mating rituals.

How are the squirrels of the Colorado River and the finches of the Galapagos significant to evolution?

Demonstrate adaptive radiation and evolution in isolated environments.

The finches of the Galapagos are an example of “Founders Effect”. What does this mean?

A small group colonizing a new area doesn't represent the full genetic diversity of the original population.

Explain the importance of natural variation within a population for natural selection.

Without natural variation, there is nothing for natural selection to act upon.

How does a changing environment play a role in natural selection?

Environmental changes alter selective pressures, driving the evolution of new adaptations.

What are the mechanisms that affect gene pools?

Mutation, gene flow, genetic drift, natural selection.

What are the 3 major eras in geologic time? What name is used to describe time before the eras?

Precambrian Era: Age of the earliest life forms. Paleozoic Era: Age of the amphibians and fish. Mesozoic Era: Age of the reptiles. Cenozoic Era: Age of the mammals.

Mass extinctions bring down the size of a gene pool. It can also significantly alter allele frequencies when the gene pool shrinks. How does this lead to an increased evolutionary rate?

Reduces genetic diversity and alters allele frequencies, leading to rapid evolutionary changes.

What is mass extinction? What happens to geologic time after a mass extinction?

Extinction of many species in a relatively short period. Geologic time is divided into new periods/epochs.

What are two common ways to determine the age of fossils? How are these two techniques used?

Relative dating and radioactive dating. Relative dating provides an estimate, radioactive dating provides a more precise age.

Define half-life

The time it takes for half of the radioactive atoms in a sample to decay.

Which technique is more specific, relative dating or radioactive dating? How do you know this?

Radioactive dating, because it gives a specific numerical age.

How are index fossils used in relative dating?

Index fossils can be useful to identify relative dates of other fossils.

What are the five main evidences of evolution discussed in class?

Fossil record, comparative anatomy, comparative embryology, biogeography, molecular biology.

Define and given an example of homologous structures, analogous structures, and vestigial structures.

Homologous: similar structure, different function (e.g., human arm and bat wing). Analogous: different structure, similar function (e.g., bird wing and insect wing). Vestigial: structure with no apparent function (e.g., human appendix).

What would be true about the comparative anatomy of 2 different species that share many homologous body structures?

They are closely related evolutionarily.

Evolutionary speaking the more homologous body structures would indicate what about 2 species?

They share a recent common ancestor.

Sharks have ampullae of lorenzini. How is this an adaptation for sharks?

Detecting electrical fields in water to find prey.

Organize the following types of organisms in order from least to most complex internal anatomy -- mammals, fish, birds

Fish, birds, mammals.

What is the function of the liver in living organisms?

Detoxification, metabolism, storage of nutrients.

How is the dark and light pattern on the dorsal and ventral side of the shark an adaptation for sharks?

Camouflage.

What is the relationship between the type of food an organism eats (herbivore, omnivore, carnivore) and the length of their intestines?

Herbivores have the longest intestines, carnivores have the shortest, and omnivores are intermediate.